Magnetic paper-feeding roller assembly

ABSTRACT

A magnetic paper-feeding roller assembly is adapted to feed a piece of paper in a machine that requires paper-feeding and that includes a casing. The magnetic paper-feeding roller assembly includes a first roller and a second roller, both of which are adapted to be pivotably mounted in the casing. The first roller is made of a magnetically attractive material. The second roller produces a magnetic force to magnetically attract the first roller toward the second roller so as to maintain a predetermined gap between the first roller and the second roller.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a paper-feeding roller assembly designed for use in a machine that requires paper-feeding, and more particularly, to a magnetic paper-feeding roller assembly that uses magnetic attraction forces to facilitate a paper-feeding operation.

2. Description of the Related Art

FIGS. 1 and 2 illustrate a conventional paper-feeding roller assembly 3 implemented in a machine, such as a photocopier, a printer, a scanner, a facsimile machine, etc. The paper-feeding roller assembly 3 includes a catch roller 31, and a press roller 32 that cooperates with the catch roller 31 to define a gap 30 therebetween. The catch roller 31 is rotatably driven by a motor (not shown) and includes a plurality of teeth 311 provided on two ends of the catch roller 31. Further, the press roller 32 includes a pair of end caps 33 that are sleeved respectively on ends of the press roller 32. A pair of spring elements 34 bias the press roller 32 to be urged toward the catch roller 31. As best shown in FIG. 2, the end caps 33 maintain a predetermined size of the gap 30 sufficient to allow a piece of paper 2 to be fed therethrough.

In the course of rotation of the rollers 31, 32, the teeth 311 of the catch roller 31 catch the piece of paper 2 that is being fed through the gap 30. To ensure that the piece of paper 2 can be fed through the gap 30 without being marked-up or damaged, the size of the gap 30 is appropriately set by the end caps 33. If the gap 10 is too large, the catching force may be insufficient to catch the piece of paper 2 to feed it through the gap 10. On the other hand, if the gap 30 is too small, the pressing force against the piece of paper 2 can become excessive, resulting in press marks being formed thereon by the teeth 311.

As a result, the manufacturing and assembly requirements of the end caps 33 and the rollers 31, 32 are high. Such high precision in manufacture can be a challenge and may complicate the assembly process. Furthermore, any other components associated with the movement of the roller assembly 3, such as the spring elements 34, may also damage the piece of paper 2.

SUMMARY OF THE INVENTION

Therefore, it is an object of the present invention to provide a magnetic paper-feeding roller assembly that is capable of overcoming the above-mentioned drawbacks of the prior art.

According to the present invention, a magnetic paper-feeding roller assembly is adapted to feed a piece of paper in a machine that requires paper-feeding and that includes a casing. The magnetic paper-feeding roller assembly includes a first roller and a second roller, both of which are adapted to be pivotably mounted in the casing. The first roller is made of a magnetically attractive material. The second roller produces a magnetic force to magnetically attract the first roller toward the second roller so as to maintain a predetermined gap between the first roller and the second roller.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiment with reference to the accompanying drawings, of which:

FIG. 1 is a perspective view of a conventional paper-feeding roller assembly;

FIG. 2 is a fragmentary front view of the paper-feeding roller assembly of FIG. 1;

FIG. 3 is a perspective view of the preferred embodiment of a magnetic paper-feeding roller assembly according to the present invention, illustrating the paper-feeding roller assembly in a state pivotably mounted in a casing of a machine;

FIG. 4 is an exploded perspective view of the preferred embodiment of the magnetic paper-feeding roller assembly according to the present invention;

FIG. 5 is a fragmentary sectional view of the preferred embodiment of the magnetic paper-feeding roller assembly in accordance with the present invention; and

FIG. 6 is a fragmentary enlarged sectional view of the preferred embodiment of the magnetic paper-feeding roller assembly in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 3, 4, 5, and 6, the preferred embodiment of a magnetic paper-feeding roller assembly of this invention is adapted to feed a piece of paper 7 in a machine, such as photocopier, a printer, a scanner, a facsimile machine, etc. The machine includes a casing 4. The magnetic paper-feeding roller assembly includes a first roller 5 and a second roller 6, both of which are adapted to be pivotably mounted in the casing 4. The first roller 5 is made of a magnetically attractive material. The second roller 6 produces a magnetic force to magnetically attract the first roller 5 toward the second roller 6 so as to maintain a predetermined gap 60 between the first roller 5 and the second roller 6.

The second roller 6 has a peripheral surface 611 and includes an anti-slip layer 612 disposed on the peripheral surface 611. The second roller 6 further includes a nonmagnetic tube 61 that has the peripheral surface 611, and at least one magnetic unit 62 disposed in the tube 61. The tube 61 has opposite ends, and, in the preferred embodiment, a pair of the magnetic units 62 are disposed in the tube 61 proximate respectively to the ends of the tube 61. In the preferred embodiment, the two magnetic units 62 are disposed in the tube 61 in such a manner that like magnetic poles of the magnetic units 62 face each other. The second roller 6 additionally includes two caps 63 that cover respectively the ends of the tube 61.

In the preferred embodiment, the tube 61 is made of a nonmagnetic stainless steel material, and the first roller 5 is made of a magnetically attractive stainless steel material. It is noted that the magnetic units 62 produce magnetic fields that extend out of the tube 61, as shown in FIG. 5. The first and second rollers 5, 6 are used to guide the passage of the piece of paper 7 through the gap 60. The piece of paper 7 is fed through the gap 60 while contacting the anti-slip layer 612 of the second roller 6 and a peripheral surface 51 of the first roller 5 which frictionally contact the piece of paper 7 to facilitate such feeding of the piece of paper 7 through the gap 60. The magnetic forces produced by the second roller 6 maintain the size of the gap 60 and also facilitate the feeding of the piece of paper 7.

Therefore, unlike the prior art described beforehand, because neither of the first and second rollers 5, 6 is formed with paper-catching teeth, the holding force of the first and second rollers 5,6 can be distributed evenly and smoothly across the piece of paper 7 without leaving pinch marks thereon and thereby avoiding damage to the piece of paper 7.

It should be noted that, in other embodiments of the present invention, the paper-feeding function can be performed without the use of the anti-slip layer 612. The anti-slip layer 612 disposed on the peripheral surface 611 of the tube 61 only enhances the holding and frictional contact force with the paper 7 during a paper-feeding operation.

While the present invention has been described in connection with what is considered the most practical and preferred embodiment, it is understood that this invention is not limited to the disclosed embodiment but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements. 

1. A magnetic paper-feeding roller assembly adapted to feed a piece of paper in a machine that requires paper-feeding, the machine including a casing, said magnetic paper-feeding roller assembly comprising: a first roller adapted to be pivotably mounted in the casing, said first roller being made of a magnetically attractive material; and a second roller adapted to be pivotably mounted in the casing, and producing a magnetic force to magnetically attract said first roller toward said second roller so as to maintain a predetermined gap between said first roller and said second roller.
 2. The magnetic paper-feeding roller assembly as claimed in claim 1, wherein said second roller has a peripheral surface, and includes an anti-slip layer disposed on said peripheral surface.
 3. The magnetic paper-feeding roller assembly as claimed in claim 2, wherein said second roller further includes a nonmagnetic tube having said peripheral surface, and at least one magnetic unit disposed in said tube.
 4. The magnetic paper-feeding roller assembly as claimed in claim 3, wherein said tube has opposite ends, and a pair of said magnetic units are disposed in said tube proximate respectively to said ends of said tube.
 5. The magnetic paper-feeding roller assembly as claimed in claim 4, wherein said magnetic units are disposed in said tube in such a manner that like magnetic poles of said magnetic units face each other.
 6. The magnetic paper-feeding roller assembly as claimed in claim 3, wherein said tube of said second roller is made of a nonmagnetic stainless steel material.
 7. The magnetic paper-feeding roller assembly as claimed in claim 3, wherein said second roller further includes two caps that cover respectively said ends of said tube.
 8. The magnetic paper-feeding roller assembly as claimed in claim 1, wherein said first roller is made of a magnetically attractive stainless steel material. 